Hi.  I have a question about database which can be easily used in Emacs.
Since I have little experience in developing database, I need some advice for it.

An entry of the database will be like,

word  : meaning 
         : date it's encountered
         : where (file or URL) it's encountered
         : how often it has shown up so far
         : etc.


There are various ways to implement such LOCAL database with Emacs.  
For example, 

hash-table
assoc
plain text
csv
splite
and maybe others.

Which method would you suggest for developing a local database like this?

Not to mention that it has to be fast for searching and organizing.

soichi